1. Technical Field
This invention relates to a keyboard apparatus, and specifically relates to a keyboard apparatus which comprises a key unit provided with a plurality of key bodies, a key supporting part for supporting each key body and a connecting part connecting the key supporting part in a pivotable manner, which are provided integrally by means of synthetic resin, and a key frame on which a key mounting part for locking the key supporting part of the key unit is provided.
2. Background Art
A keyboard apparatus as shown in FIG. 17 is disclosed for example in Japanese Patent No. 3082696. As shown in the same drawing, a keyboard apparatus comprises a white key unit 10 and a black key unit 11 serving as key units, and a key frame 20. The white key unit 10 and the black key unit 11 are, respectively, provided with one or more of key body 12 for stroking operation, a key supporting part 13 supporting the far end of the key body 12 remote from a player in a depth direction Y1 of the key frame 20, and a connecting part 14 connecting the key body 12 to the key supporting part 13 in a pivotable manner in a key-stroking direction Y2. These parts are provided integrally by means of synthetic resin.
The key supporting parts 13 of the white key unit 10 and the black key unit 11, respectively, have a first screw hole 16 into which a screw N for mounting to the key frame 20 is inserted. The far side remote from a player of the key supporting part 13 of the black key unit 11 is provided with an arm section 13A extending toward the lower side of the key frame 20 and a first engagement section 13B provided at the lower end of the arm section 13A which projects toward the far side from a player.
The key frame 20 has an upper surface portion 22 and a first reinforcement rib 23. The upper surface portion 22 is provided like a plate approximately perpendicular to the key-stroking direction Y2. The far side of the upper surface portion 22 away from a player in the depth direction Y1 is provided with a key mounting part 22A to which the key supporting part 13 is locked.
The key mounting part 22A has a boss 21 extending toward the lower side, and the boss 21 has a second screw hole 21A. The second screw hole 21A has a thread groove to threadably mate with the screw N. The upper surface portion 22 disposed on the farther side than the key mounting part 22A from a play has an insertion hole 29 into which the first engagement section 13B is inserted. The first reinforcement rib 23 is provided at the lower side of the upper surface portion 22 of the key frame 20, and serves to reinforce the key mounting part 22A which not so strong against applied force.
Next, described below is the mounting work of the white key unit 10 and the black key unit 11 having the configurations as described above to the key frame 20. First, the key supporting parts 13 of two white key units 10 are placed with one laid on another so that their first screw holes 16 in the key mounting parts 13 are aligned. On them, the key supporting part 13 of a black key unit 11 is laid so that their first screw holes 16 are aligned.
Then, with the key supporting part 13 of one black key unit 11 are laid on those of two white key units 10, the first engagement section 13B of the black key unit 11 is inserted into the insertion hole 29. This engages the first engagement section 13B and a second engagement section 27A which is the edge portion of the far side of the insertion hole 29 away from a player, so that the white key units 10 and the black key unit 11 are temporarily fixed to the key frame 20. This temporary fixation aligns the first screw holes 16 in the key supporting part 13 of the white key unit 10 and the black key unit 11 with the second screw hole 21A in the key frame 20. Then, the screw N is inserted into the first screw holes 16 and threadably mated with the second screw hole 21A, and the key supporting parts 13 of the white key units 10 and the black key unit 11 are locked to the key mounting part 22A of the key frame 20.
However, the conventional configuration as shown in FIG. 17, which is provided with the first engagement section 13B projecting below the key mounting part 22A, has a problem of reducing space efficiency as well as the degree of freedom of mounting component parts such as a hammer, basal plate, cushion and speaker, if mounted below the key mounting part 22A.
In addition, the conventional configuration a shown in FIG. 17, which is provided with a boss 21 extending below a key mounting part 22A of a key frame 20, has a problem of reducing space efficiency as well as the degree of freedom of mounting due to the boss 21. It has further problem of interfering with the improvement of production efficiency which can be attained by using standardized screws N, because the screws N need to be longer than ordinary screws in order to be inserted into first screw holes 16 and second screw holes 21A provided both in the key supporting part 13 and the key frame 20.
The conventional configuration as shown in FIG. 17, which is provided with the first reinforcement rib 23 extending below the key mounting part 22A, has a problem of reducing space efficiency as well as the degree of freedom of mounting also due to the first reinforcement rib 23.